How "illegal" are high flow cats???

[ArizonaG35]

I understand that neither Nicoclub.com nor it's affiliates and/or sponsors condone, encourage or endorse the use of "less than legal" forms of performance modification for public use... blah blah blah...

With that being said, I'm considering adding the Stillen Dual catback exhaust to my G and thought that since I'm dropping the dough, would it be worth it to add the new Stillen High performance Catalytic converters simultaneously? (These were just added to http://www.everythingg35.com) Link: http://www.g35parts.com/9083/o...d=713

My question is:How "Illegal" is this modification? Are we talking like "O.J Simpson Illegal" or "Jaywalking Illegal"?I'm assuming that the cops don't check under your car... so this would probably only be detected during an emissions inspection? Is this a large ticket? anyone ever been fined?

Thanks for the advice!Dave

[Sentientbydesign]

I remember speaking to Brian Catts from Cattman Performance regarding an exhaust system for my I30.

He basically said that the legality is very much based on where you live. California having the strictest emmisions laws would be a bad place to mess with emissions equipment.

He also said that there are hi-flow cats that are actually more efficient that the factory installed ones.

So, that being said, if you can get one that meets or exceeds the emissions requirements for your car AND doesn't get too loud, since there are many city ordinances in effect on obnoxious sound, then the hi-flow cat should be fine.

In California, if you get caught with something that doesn't meet standards, they fine you and make you tow it to a certified mechanic to have it replaced.

No replacing it yourself, no driving it there, and NO installing the original one, because it's used.

You might verify all of that with the other members, but that is what I've read/researched.

[gwoods]

Hey buddy,

In Phoenix we do have on ramp 'sniffer' vans that will get your picture and ticket if you fail a sniffer emissions test getting on the freeway.

That being said I drove my Hemi Ram for a year with no cats and had no problems. I even traded it on the G with no cats... stock exhaust went with the truck.

If you can afford high flow cat's I'd do it just to avoid the constant 0420/0430 codes that no cats will produce. You can use spark plug anti foulers to space the rear 02 sensors out of the exhaust flow far enough to simulate cats.

We can make it work either way but I'd do high flow cats if it were my G.

Jeff

[Jacko3]

I don't know how true it is, but I heard that High Flow cats do reduce the low end torque on the car. I don't know how true this is? But I do know larger air flow tunnels tend to cause some slight reduction in fluid pressure. Maybe the person I was speaking to was confusing a drop in pressure with a drop in torque. Anyone out there with any ideas on this or heard anything similar? This si why I haven't installed it yet.

[rn79870]

I'll start the answer to your question and I'm sure someone else will be along to finish what I miss. There are a few things to consider.

1. With a 2007 Infiniti, you have a warranty that may be voided by this. I don't know whether Infiniti would or would not. But it is something that you need to consider.

2. The EPA, the Federal overseer of emission issues, has approved some high flow cats. Whether you can change a working cat for a high flow cat is a gray area. I've heard that you can only change defective cats. Say for instance, you drove in Mexico and accidentally used leaded fuel. This would probably justify a change to high flow cats.

3. Your state may have something equivalent to the California Air Resource Board (CARB), that oversee vehicle emissions at your state level. They will have to have approved high flow cats, but again, there may be issues of voluntary changing a working system.

Probably the biggest problem you would have would be with the 1st. item, that is, would Infiniti void your warranty. For that, I'd ask the Infiniti dealer and not rely on too many other opinions.

I've seen cars in the past with changed cats and never gave it a second thought, as long as the emissions were within specs when testing. In fact, I would bet the average smog mech wouldn't recognize a changed cat 1 out of 20 times. Personally, If I were modifying my G, I would look into HF cats and I'd feel pretty confident/safe/legal doing it. But I'm not because my baby is fine, just like she is.
Modified by rn79870 at 12:16 PM 2/15/2008

[C-Kwik]

Infiniti can't void your entire warranty over a cat. They can however deny any warranty claims for the aftermarket cat or any problems that were caused by the aftermarket cat.

I can't recall exactly, but aftermarket cats aren't allowed to replace factory cats anymore. This may be a California thing, but replacement cats must be OE. This does not preclude one from adding another cat after the factory cats though.

Generally, If I were to go with a high flow cat, I would stick to name brands. Avoid the cheaper ones. Considering the amount of presious metals that go into a cat to catalyze the gasses, one can assume a cheap cat is not going to have as much of the material necessary. A catalytic converter basically has a brick made of some material with specific quantities of certain metals coating them. The brick, when viewed from either end has a sort of honeycomb appearance where each hole is a channel that goes down to the other end.

There are two methods that can be used to iincrease flow. One is to simply reduce the number of channels, thereby reduciing the amount of material that can impede flow. This reduces the surface area that is available to come into contact with the air going through it, causing a drop in catalyzation performance. I speculate that this is why the restriction on replacing with non-OE cats is in place.

The other method is to simply increase the cross-sectional area. By simply having more of the same sized channels available, more flow can be achieved without reducing the effectiveness of the catalytic converter (except maybe requiring a slightly longer light-off period due to an increase in mass).

As for power, high flow cats can have a similar effect on power as a larger exhaust might. Perhaps to a limited extent, depending on the vehicle. Backpressure on a car is never good in that of itself. Higher exhaust gas velocity is good though. It helps with the scavenging effect that occurs in the cylinder when the exhaust valves open. The catch 22 is that to increase exhaust gas velocity, it requires smaller pipes, which inherently have more backpressure (especially at higher RPM's). In most cases however, the piping diameter will be the most relevant factor for exhaust gas velocity.

[rn79870]

I can't recall exactly, but aftermarket cats aren't allowed to replace factory cats anymore. This may be a California thing, but replacement cats must be OE. This does not preclude one from adding another cat after the factory cats though.

First of all, adding an additional cat would quite possibly effect the performance of the vehicle in a negative way. So that isn't a consideration.

Secondly, I believe your blanket illegal statement is over broad and, and not technically correct. Here is why...

California Vehicle Code, Section 27156 provides that an emission system shall not be modified, as well as those times WHEN emission system modification will be allowed. (h)This section shall not apply to an alteration, modification, or modifying device, apparatus, or mechanism found by resolution of the State Air Resources Board to do either of the following: (1) Not to reduce the effectiveness of a required motor vehicle pollution control device.(2) To result in emissions from the modified or altered vehicle that are at levels that comply with existing state or federal standards for that model-year of the vehicle being modified or converted.

Therefore, aftermarket High Flow Catalytic Converters could be permissible in California, if certain conditions are met. Not the least of which would be that the replacement unit must be certified by, and carry an Executive Order number (EO) from the California Air Resource Board.

The procedures for obtaining this EO is specific and explained herehttp://www.arb.ca.gov/regact/2...1.pdf

The California Air Resource Board, on its web site, provides:A legal aftermarket catalyst is one that is listed in an ARB approved manufacturers catalogue for the year, make, model, and engine size of vehicle on which it is being installed. Manufacturers of aftermarket catalytic converters must obtain an Executive Order for their products from the Air Resources Board in order to be listed in an approved catalogue.http://www.arb.ca.gov/msprog/aftermkt/replace.htm

For instance, Stillen advertises that their converters are not CARB legal, hence we can expect that they are in violation of the law.

Random Technologies claims: This design, which meets Federal EPA and California ARB requirements, enables virtually any vehicle with a properly tuned engine to meet emissions standards with little, if any power losshttp://www.randomtechnology.com/(I’m taking their word that they meet requirements, not merely standards - IE. all converts meet standards, but few meet requirements)

The bottom line is that replacement cats need not be OE, but must carry an EO number to be assured of legality. The issue of "replacement" may well address a defective device, however, the exceptions specific to the CVC, and the CARB rules appear to muddy that requirement as well. I think adding CARB approved High Flow Cats would be both legal and permissible for California.

[Sentientbydesign]

I know this probably belongs in a different threads somewhere in the technical section, but would it be feasible to have a multi-path exhaust to deal with the catch 22?

Similar in concept to Toyota's VVTI-L. Their system allows for "higher" valve lift when a certain RPM range is reached. Could a secondary exhaust pipe be opened when a high enough RPM range was reached? OR use a variable diameter pipe mechanism?

Oh ****...did I just give away my patent? lol

[rn79870]

I don't have any idea if that would work but my initial GUESS would be that it would just confuse the heck out of the ECU.

[Sentientbydesign]

Sorry, I should have specified. I meant engineered that way for the vehicle. Not just a bolt-on.

[Beancooker]

Hey buddy,

In Phoenix we do have on ramp 'sniffer' vans that will get your picture and ticket if you fail a sniffer emissions test getting on the freeway.

Wait a minute, there is a van that can get an approximation of how dirty your exhaust is when you're driving close to it on the "on ramp"? How does that work? Usually there needs to be a "sniffer" jammed up the tailpipe for a minute or so to get an accurate reading...

***EDIT***

I just googled "roadside emissions" and that is the biggest bunch of BS that I've heard in a while. I'll enjoy my emissions free registration while it lasts...

[rn79870]

They have them in California too. They shoot a beam across the road to a reflector on the other side. Somehow that beam detects the particulate in the air. They are typically on up hill type on ramps.



Up by the last orange cones you can see the "sniffers" on the side of the road. You can see the camera set up to snap your license plate too.The only difference is that the ones I've seen are by the metered on ramps to the freeways and are trailers not vans. This is a picture from the 91/215 interchange (southern Riverside County).

[!979TransAm]

Sentient could you elaborate on your idea? Do you mean having a seperate type of exhaust that opens? You could program a kind of electric cut out to do that in your exhaust at a certain rpm, but I rather just push the button for straight pipes and not have the computer decide.

[AZhitman]

Quick answer -

Not enough gain to justify the cost. New car should have perfectly functional free-flowing cats. The newer design of catalytic converters is very non-restrictive... Keep your stockers.

[C-Kwik]

I don't disagree that adding another cat might negatively affect performance. But it is a practice that I've seen done. It might be that they do this if they use a not so "legal" cat.

As for the laws about replacing with an OE cat, I know I heard or read it somewhere, but as I can't find th source, I digress. The info you posted does contradict the possibility of it quite a bit so I'll assume I was inaccurate. However, some poking around reveals that per the EPA, you are not allowed to replace the OE cat unless there is something wrong with it. While unlikely that they may catch you, there is potential that you might be fined for it.

http://www.epa.gov/OMS/cert/factshts/catcvrts.pdf

[joe603]

I know this probably belongs in a different threads somewhere in the technical section, but would it be feasible to have a multi-path exhaust to deal with the catch 22?

Similar in concept to Toyota's VVTI-L. Their system allows for "higher" valve lift when a certain RPM range is reached. Could a secondary exhaust pipe be opened when a high enough RPM range was reached? OR use a variable diameter pipe mechanism?

Oh ****...did I just give away my patent? lol

This is the principle behind some cars "sport" mode. I know my 3000gt opened another port on the rear section of the exhaust via a valve when you pressed the sport mode. This gives the exhaust a free-flowing characteristic to give you more power. I'm sure other car's (high end) do it automatically...

[gwoods]

Wait a minute, there is a van that can get an approximation of how dirty your exhaust is when you're driving close to it on the "on ramp"? How does that work? Usually there needs to be a "sniffer" jammed up the tailpipe for a minute or so to get an accurate reading...

***EDIT***

I just googled "roadside emissions" and that is the biggest bunch of BS that I've heard in a while. I'll enjoy my emissions free registration while it lasts...

Yeah it sucks but you know we do have global warming now

Tyler had a 76 Camaro it came with a 305.... we built a badas$ small block 400 and had a 350 built for it that was ratchet shifted manually. Everytime he saw those vans hed have to kill the motor and coast buy then fire it back up.

I didn't have any trouble with my hemi..... but for a while I ran glass packs right off he headers and I had a few police camp on my bumper just waiting for a reason to stop me. The truck was so loud when I remote started it the dishes in the kitchen rattled

[Sentientbydesign]

This is the principle behind some cars "sport" mode. I know my 3000gt opened another port on the rear section of the exhaust via a valve when you pressed the sport mode. This gives the exhaust a free-flowing characteristic to give you more power. I'm sure other car's (high end) do it automatically...

Very interesting Joe. I'll do some research on it. I was thinking about having the "auxillary" system kick in once a certain RPM range was reached. Like V-tech or VVTI-L.

I thank God, that I've never been pulled over and had my I30 inspected. The exhaust is legal, but the intake is far from it. Just started her up yesterday since she's been sitting in front of the house collecting dust, and I LOVE the sound of that car. Too bad I can't get the G to sound that nice lol.